The present invention relates to a three-dimensional graphics display system that can represent a three-dimensional virtual space. In particular, the present invention relates to a three-dimensional graphics display system with joint use of a two-dimensional image representation, representing background, resting objects and characters or parts thereof with flat two-dimensional images arranged in the three-dimensional virtual space.
In recent years, the ever higher performance of computer systems and the continuous development of multimedia processing techniques has led to environments that can process high-level three-dimensional computer graphics even on personal computers. Dedicated accelerator boards for processing of three-dimensional computer graphics are under continuous development. Games that animate characters or objects such as artificial creatures usually store the object data mainly in form of polygons. To render the object in a fast drawing procedure and to create images with a high flexibility, a texture is wrapped around and pasted to the created polygon mesh.
On the other hand, graphic formats for two-dimensional images are also wide-spread. From a natural image captured with a digital camera or a scanner, high-quality two-dimensional computer graphic images can be created with various computer graphic software packages and authoring tools.
Thus, with three-dimensional graphics processing, images of three-dimensional objects can be created with a high flexibility, whereas with two-dimensional image processing, the creation of high-quality static images is possible. Therefore, by making use of their respective characteristics, the user can take advantage of the two approaches, depending on his goals.
In the past, there have been attempts to simultaneously represent three-dimensional graphics representations and two-dimensional image representations in one three-dimensional virtual space in order to benefit from their respective merits by jointly using three-dimensional graphics and two-dimensional images. However, these attempts consisted largely of pasting two-dimensional images onto the surface of a three-dimensional object. For example, a three-dimensional polygon having a large external surface was arranged in three-dimensional space, and two-dimensional images, such as a texture, were wrapped around and pasted onto this external surface.
As has been mentioned above, two-dimensional images and three-dimensional graphics both have their merits, and there have been attempts to use both three-dimensional and two-dimensional image representations at the same time. However, there are problems with the conventional approaches: With three-dimensional graphics processing, images can be created with a high flexibility, but the number of polygons into which an object can be divided is limited owing to the limits of the computer processing capabilities. Thus, it is difficult to create high-quality, high-definition three-dimensional objects, and overly complicated scenes cannot be drawn. On the other hand, with two-dimensional image processing, high-quality, high-definition rendering is possible, but it cannot be used for movable objects, and a display from another viewpoint is not possible. Therefore, when jointly using three-dimensional graphics and two-dimensional images by pasting a two-dimensional image onto the surface of a three-dimensional object, the quality of the two-dimensional image depends on the quality of the three-dimensional graphics, and a high-quality image cannot be attained due to these limitations, so that the characteristics of three-dimensional graphics and two-dimensional images could not be exploited in their joint use.
In the present invention, a two-dimensional image is not only wrapped around and pasted onto the external surface of a three-dimensional object as in the prior art, but the present invention is adapted to the representation of two-dimensional images in the presence of objects in the three-dimensional virtual space. First, images of static objects for which images from a different viewpoint are not necessary in that scene correspond to xe2x80x9ctwo-dimensional image representationsxe2x80x9d. Second, object portions that are elements of three-dimensional objects can also correspond to xe2x80x9ctwo-dimensional image representationsxe2x80x9d. For example, an object portion such as the shadow of a three-dimensional object moves and deforms depending on the three-dimensional object, but a three-dimensional display of such an object is not necessary and it can be adapted for two-dimensional image representation. Thus, if it were possible to simultaneously render two-dimensional image representations, the data processing amount could be reduced.
An important feature for the simultaneous rendering and display of two-dimensional images and three-dimensional images is that it becomes necessary to control the positions and overlapping in the three-dimensional space of the two. Moreover, it is preferable that in an environment for simultaneous representation of two-dimensional images and three-dimensional images, image processing techniques such as lighting and shading can be applied.
The present invention has been developed under consideration of these aspects. It is a purpose of the present invention to provide a three-dimensional graphics display system wherein objects corresponding to three-dimensional image representations can be represented as three-dimensional objects, objects that can be represented as two-dimensional images are represented as flat two-dimensional images arranged in a three-dimensional virtual space, both two-dimensional and three-dimensional objects can be rendered simultaneously in the three-dimensional virtual space, and a reduction of the data processing amount and an increase of the data processing speed can be achieved.
A three-dimensional graphics display system according to the present invention is characterized in that as input data the system uses image data that comprises (a) three-dimensional polygon data for a three-dimensional object representing a three-dimensional image and (b) two-dimensional image representation data comprising (i) two-dimensional image data for a two-dimensional image representation object representing a three-dimensional object as a two-dimensional image arranged in a three-dimensional virtual space and (ii) a Z-value representing a depth. The three-dimensional graphics display system comprises a data input part; an object perspective control part for determining a perspective order of objects based on the input data; a rendering process part for overlappingly rendering objects in order from a furthest object to a nearest object, based on the determined perspective order, to correctly represent overlap due to perspective representation; an output part for displaying a rendering result. Three-dimensional objects and two-dimensional image representation objects are rendered simultaneously in the three-dimensional virtual space.
According to this configuration, three-dimensional objects and two-dimensional image representation objects can be rendered simultaneously in the three-dimensional virtual space, the data processing amount can be reduced, and the data processing speed can be increased.
It is preferable that this three-dimensional graphics display system further comprises an object exclusion control part for exclusion-controlling an area occupied by the three-dimensional object and an area occupied by the two-dimensional image representation object, and the system can represent a virtual collision in the three-dimensional virtual space between the three-dimensional object and the two-dimensional image representation object, the virtual collision being caused by a movement of the three-dimensional object.
According to this configuration, the presence of two-dimensional image representation objects in the three-dimensional virtual space can be represented more naturally.
It is preferable that in this three-dimensional graphics display, the input data further comprises supplementary three-dimensional polygon data that is three-dimensional polygon data associated with the two-dimensional image representation data for the two-dimensional image representation object, the supplementary three-dimensional polygon data representing a three-dimensional object that is the basis of the two-dimensional image representation object as a three-dimensional image; the system further comprises a data switching part for switching from two-dimensional image representation data to supplementary three-dimensional polygon data; and the data switching part selectively switches from two-dimensional image representation data to supplementary three-dimensional polygon data to represent a two-dimensional image representation object as a three-dimensional object.
According to this configuration, the system can switch from static two-dimensional image representation objects to movable three-dimensional objects, depending on the situation. For example, if there is a virtual collision in the three-dimensional virtual space, the movement or fall of such object can be represented, so that a more flexible and natural representation of the three-dimensional virtual space is possible.
It is preferable that in this three-dimensional graphics display system, the input data further comprises object-relation information that is associated with a relation between image data of object portions and other object portions as data for object portions forming a character in the three-dimensional virtual space; for each object portion, the rendering process part performs a rendering process based on the three-dimensional polygon data or the two-dimensional image representation data for the object portion and the object-relation information; and a movement of the character is represented by renewing the object-relation information.
According to this configuration, one character can be configured as being rendered simultaneously by three-dimensional object portions and two-dimensional image representation object portions. Moreover, due to the renewal of data for certain object portions, the data for related object portions is renewed, so that it is not necessary to provide, process and renew independent data for all object portions. Thus, a reduction of data processing and an increase in the data processing speed can be attained.
It is preferable that this three-dimensional graphics display system further comprises a two-dimensional image processing part for image processing of two-dimensional images; the input data further comprises two-dimensional image processing instruction data for instructing two-dimensional image processing of the two-dimensional image representation object; and based on the two-dimensional image processing instruction data, the two-dimensional image processing part performs two-dimensional image processing of the two-dimensional image representation data for the two-dimensional image representation object.
According to this configuration, two-dimensional image processing, such as deformation, shading or edge emphasis, can be applied to two-dimensional image representation objects, so that more flexible image processing effects can be attained.
It is preferable that in this three-dimensional graphics display system, a child object and a parent object are in a perspective order to each other in the three-dimensional virtual space, the child object is a two-dimensional image representation object displayed by overlapping, and the child object is drawn into the parent object; the input data further comprises (a) two-dimensional image representation data for the parent object, and (b) hierarchical information expressing the hierarchical relationship between the parent object and the child object; the rendering process part performs a rendering process based on image data of the parent object, an object that is not in a hierarchical relationship with the parent object, and the child object, wherein the other object is between the parent object and the child object in the perspective order determined by the object perspective control part.
According to this configuration, the number of rendering processes for child objects when there is no other object between the child object and the parent object can be decreased, so that a reduction of data processing and an increase in the data processing speed can be attained. Moreover, when there is another object between the child object and the parent object, the child object can be correctly overlapped, and the perspective order in the three-dimensional virtual space can be correctly represented.
A computer-readable recording medium according to the present invention stores a program for displaying an image of a three-dimensional object on an output device based on three-dimensional polygon data. The program performs an input step of inputting (a) three-dimensional polygon data for a three-dimensional object representing a three-dimensional image and (b) two-dimensional image representation data comprising (i) a two-dimensional image for a two-dimensional image representation object representing a three-dimensional object as a two-dimensional image arranged in a three-dimensional virtual space and (ii) a Z-value representing a depth; a determination step of determining a perspective order of objects based on the input data; a rendering step of overlappingly rendering objects in order from a furthest object to a nearest object, based on the determined perspective order, to correctly represent overlap due to perspective representation; and an output part for displaying a rendering result. Three-dimensional objects and two-dimensional image representation objects are rendered simultaneously in the three-dimensional virtual space.
According to this configuration, three-dimensional objects and two-dimensional image representation objects can be rendered simultaneously in the three-dimensional virtual space on a computer.